Trenching assembly

Abstract

A trenching assembly used to cut a narrow trench in the ground surface. The trenching assembly comprises an attachment frame connected to a hood assembly via a linkage assembly. The attachment frame may be attached to the rear end of a work machine. A rotatable blade is disposed within a cavity defined by the hood assembly. The hood assembly may rotate about two different axes relative to the linkage assembly, and the linkage assembly may rotate about two different axes relative to the attachment frame. The trenching assembly uses a pair of accumulators to hydraulically rotate the linkage assembly about a horizontal axis relative to the frame in response changes in depth of the ground surface being cut by the blade. The linkage assembly may be hydraulically rotated using the accumulators without input from the operator.

The invention claimed is: 
     
       1. A trenching assembly comprising:
 a frame that extends along a longitudinal axis; 
 a hood assembly having a surface-engaging member and defining a cavity; 
 a linkage assembly interconnecting the frame and the hood assembly and comprising a first hydraulic cylinder, in which the linkage assembly is pivotable adjacent the frame about a horizontal axis; and in which the hood assembly is pivotable relative to the linkage assembly about a first hood axis that is perpendicular to the longitudinal axis of the frame; and 
 a rotatable blade at least partially positioned within the cavity, in which the blade is vertically positionable relative to the hood assembly. 
 
     
     
       2. The trenching assembly of  claim 1  in which the hood assembly is characterized by a pair of opposed sides, and in which the linkage assembly comprises a pivot arm attached to only a single side of the hood assembly. 
     
     
       3. The trenching assembly of  claim 2  in which the pivot arm is releasably attached to the single side of the hood assembly. 
     
     
       4. The trenching assembly of  claim 2  in which the linkage assembly further comprises a mount and a first arm, in which the mount is attached to the frame and the first arm interconnects the mount and the pivot arm. 
     
     
       5. The trenching assembly of  claim 2  in which the hood assembly is rotatable relative to the pivot arm. 
     
     
       6. The trenching assembly of  claim 2  further comprising a pin projecting from the single side of the hood assembly that is releasably engageable with the pivot arm. 
     
     
       7. The trenching assembly of  claim 2  in which the pivot arm has a flat bottom surface that is positioned parallel to the surface-engaging member. 
     
     
       8. The trenching assembly of  claim 2  in which the pivot arm is attached to the single side of the hood assembly via a third hydraulic cylinder. 
     
     
       9. The trenching assembly of  claim 1  in which activation of the first hydraulic cylinder pivots the linkage assembly about the horizontal axis. 
     
     
       10. The trenching assembly of  claim 1  further comprising an accumulator supported on the frame, in which the first hydraulic cylinder is connected via a hydraulic line to the accumulator. 
     
     
       11. The trenching assembly of  claim 1  further comprising a first and a second accumulator, the first hydraulic cylinder further comprising a cylinder and a piston, and in which the cylinder is connected via a first hydraulic line to the first accumulator and the piston is connected via a second hydraulic line to the second accumulator. 
     
     
       12. The trenching assembly of  claim 1  in which the blade is rotatable about a blade axis that is orthogonal to the first hood axis. 
     
     
       13. The trenching assembly of  claim 1  in which the hood assembly is rotatable about a second hood axis that is perpendicular to the first hood axis. 
     
     
       14. The trenching assembly of  claim 13  in which the hood assembly is rotatable about the second hood axis relative to the first hood axis within an angular range of about 15 degrees. 
     
     
       15. The trenching assembly of  claim 1  further comprising a second hydraulic cylinder configured to pivot the hood assembly about the first hood axis. 
     
     
       16. The trenching assembly of  claim 1  in which the linkage assembly is pivotable adjacent the frame about a vertical axis. 
     
     
       17. The trenching assembly of  claim 1  in which the linkage assembly is pivotable adjacent the hood assembly about a horizontal axis. 
     
     
       18. The trenching assembly of  claim 1  in which the linkage assembly is movable along an axis parallel to the longitudinal axis of the frame. 
     
     
       19. The trenching assembly of  claim 1  in which the linkage assembly comprises a pair of spaced and longitudinally offset arms joined by a cross member. 
     
     
       20. A work machine comprising:
 a frame; 
 a motive means for moving the frame; and 
 the trenching assembly of  claim 1 . 
 
     
     
       21. A method for cutting a narrow trench in a direction of travel using a rotatable blade attached to a frame via a linkage assembly, wherein the rotatable blade is disposed within a cavity defined by a hood assembly having a surface-engaging member, the method comprising:
 positioning the surface-engaging member on the surface adjacent the blade; 
 adjusting a vertical position of the blade relative to the surface engaging member to achieve the desired trench depth; 
 rotating the blade to cut a trench; 
 translating the frame in the direction of travel; and 
 pivoting the hood assembly relative the linkage assembly about an axis parallel to the direction of travel. 
 
     
     
       22. The method of  claim 21  further comprising pivoting the hood assembly about an axis perpendicular to the direction of travel such that the surface engaging member is positioned at a non-zero angle relative to the frame. 
     
     
       23. The method of  claim 21  further comprising rotating the linkage assembly adjacent the frame about a vertical axis. 
     
     
       24. The method of  claim 21  further comprising rotating the hood assembly relative to an axis parallel to the direction of travel. 
     
     
       25. The method of  claim 21  further comprising pivoting the linkage assembly about an axis perpendicular to the direction of travel by passing hydraulic fluid between an accumulator supported on the frame and a hydraulic cylinder attached to the linkage assembly.